Nimitz was the leading US Navy authority on submarines. Qualified in submarines during his early years, he later oversaw the conversion of these vessels' propulsion from gasoline to diesel, and then later was key in acquiring approval to build the world's first nuclear-powered submarine, USS Nautilus , whose propulsion system later completely superseded diesel-powered submarines in the US. He also, beginning in , was the Navy's leading developer of underway replenishment techniques, the tool which during the Pacific war would allow the US fleet to operate away from port almost indefinitely.
He was the United States' last surviving officer who served in the rank of fleet admiral. The USS Nimitz supercarrier , the lead ship of her class , is named after him. His frail, rheumatic father had died six months earlier, on 14 August Nimitz's brother. The best way to get along with either is to learn all you can, then do your best and don't worry β especially about things over which you have no control". Originally, Nimitz applied to West Point in hopes of becoming an Army officer, but no appointments were available.
James L. Slayden , US Representative for Texas's 12th congressional district , told him that he had one appointment available for the United States Naval Academy and that he would award it to the best-qualified candidate. Nimitz felt that this was his only opportunity for further education and spent extra time studying to earn the appointment.
He was appointed to the Naval Academy by Slayden in , and graduated with distinction on 30 January , seventh in a class of Bowen Sr. Cook, Wilhelm L. Friedell , William R.
Furlong , Stanford C. Hooper , Royal E. Ingersoll , Herbert F. Newton , Harry E. Shoemaker, John M. Smeallie, John W. Wilcox Jr. In September , he was transferred to the cruiser Baltimore ; on 31 January , after the two years at sea as a warrant officer then required by law, he was commissioned as an ensign.
